LOS ANGELES (AP) - A grand jury has found police chases in Los Angeles are causing “unnecessary bystander injuries and deaths” and recommended police and sheriff’s officers undergo additional training to reduce the likelihood of crashes during pursuits, according to a report released Tuesday.

The Los Angeles County civil grand jury report found three people were killed and 45 people were injured during 421 pursuits in the county from October 2015 until 2016 and concluded that most of the pursuits were not provoked by serious crimes.

The report, citing information from the California Highway Patrol, found that 17 percent of pursuits ended in crashes with the possibility of injuries or death. Sixty-seven percent of the pursuits ended with arrests, the grand jury found.

The grand jury also found that neither Los Angeles police nor sheriff’s officials have policies in place for recurring or continued vehicle pursuit training.

“Police pursuits are inherently dangerous and that is why the Los Angeles Police Department takes every step to develop tactics and mitigate the risk posed by these dangerous interactions,” Los Angeles police spokesman Josh Rubenstein said in a statement. “We are constantly reviewing our policies and procedures to ensure they support what we value the most: the preservation of life.”

The report also criticized the Los Angeles County sheriff’s department’s training facility, saying it was “substandard.” A sheriff’s official said the department is in the process of acquiring a new training center for emergency drivers.

Deputies receive annual training on the department’s pursuit policy and also undergo emergency vehicle training every two years, sheriff’s Capt. Scott Gage said. The sheriff’s department - the largest in the U.S. - has one of the most restrictive pursuit policies in the nation, Gage said.

The policy only allows deputies to pursue drivers for serious felony offenses, confirmed stolen cars or potentially reckless drunken drivers, Gage said. The department’s policy expressly prohibits deputies from chasing someone fleeing after being stopped from an infraction, he said.

“We’re always looking to do better and have more training in this field,” Gage said. “There’s nobody that’s going to say the training is enough for our folks.”